Fan Noise


Minor erosion of fan parts due to the presence of dust is quite common. However, in some applications erosion of fan blades and casing due to dust-laden air is very serious. This is one of the causes of failure of I.D fans.

When dust particles directly hit the moving blades, they cause cracking of the blades, whereas flow of abrasive dust through the passages causing scraping action leading to surface erosion. Some aspects of dust erosions are given bellow.

 The worn-out blade surfaces alter the geometry of the flow far from the design. This is     reflected in poor fan performance.
 If considerable erosion has occurred in highly stressed regions, the affected part can be     suddenly fail after some time.
 The wear of the rotor due to dust erosion is not axisymmetric. This leads to imbalance of the     rotor and increases the load on bearings.
 The imbalance and the resulting vibration are further increased due to the collection of the     dust in the pockets created by erosion.

Dust particles collected in the stalled regions of the fan which erodes the surface by a milling action.

In view of erosion problems, the selection of the right type of fan is important. However a fan which suffers least due to erosion may not always be the best choice for given application. Dust erosion has been found to be inversely proportional to the pressure coefficient. It has found that erosion is more serious in axial type fan.

Aerotech can minimize the erosion problem which is:

Employing a more efficient dust removing apparatus.
Regulating fan speeds at part load.
Reducing stratification.
Employing large and low speed fan.
Providing erosion shields on the blades.